How to sort ArrayList alphabetically by fields that contain non-english characters? Java

Question

I have an ArrayList of custom objects that I want to sort alphabetically. The problem is that the field I want to sort it by sometimes contains non-english characters, like á or é. I wanted to do this by using Collections.sort(), but with this method, the items with non-english strings in their fields don't get sorted correctly.

This is what I've tried:

public List<Video> sortDatabase(List<Video> videos){
        List<Video> sortedList = new ArrayList<>(videos);
        Collections.sort(sortedList, new Comparator<Video>() {
            @Override
            public int compare(Video video, Video t1) {
                return video.getTitle().compareTo(t1.getTitle());
            }
        });
        return orderedList;
    }

EDIT
I am using Android Studio with minSdkVersion 21

Bence · Accepted Answer · 2021-01-21T14:29:29.450

I've found a good answer here. This is how it looks like in my case:

public List<Video> sortDatabase(List<Video> videos){
        List<Video> sortedList = new ArrayList<>(videos);
        orderedList.sort(new VideoComparator());
        return orderedList;
    }

private static class VideoComparator implements Comparator<Video>{
            Collator spCollator = Collator.getInstance(new Locale("hu", "HU"));
            public int compare (Video e1, Video e2){
                return spCollator.compare(e1.getTitle(), e2.getTitle());
            }
        }

In my case, the Locale had to be constructed with ("hu", "HU"). You can check all supported languages here

This solution works fine, however, I am trying to use this for an Android application where this method only works with API level 24 or higher. So if anybody has a different solution, I will make that the accepted answer.

You don’t need to implement a comparator by hand. Just use `orderedList.sort( Comparator.comparing(Video::getTitle, Collator.getInstance(new Locale("hu", "HU")));` — Holger, Jan 22 '21 at 17:10

score 0 · Answer 2 · answered Jan 21 '21 at 14:44

but with this method, the items with non-english (sic) strings in their fields don't get sorted correctly.

Are you sure that's the problem? Could it be that maybe you do not understand what is involved in sorting? I am pretty sure that the problem is the Unicode values of the characters. Characters are organized in character sets. The entire English language characters have a Unicode value lower or higher than characters from other languages, thus giving the impression that the sorting went wrong.

Maybe you should take a look at the Unicode chart to fully understand what I am saying.

How to sort ArrayList alphabetically by fields that contain non-english characters? Java

2 Answers2